Under the NIEHS SBIR, Biopraxis proposes to develop a high-throughput Doodlebug for screening large populations and large numbers of environmental samples for diverse chemical contaminants, including heavy metals, PCBs, pesticides, antibiotic residues, and naturally occurring toxins. Doodlebug is a new, reagentless biochip technology under development for the detection of (CBW) agents and explosives. Phase I will show that Doodlebug can detect low- molecular-weight contaminants; individually identify cross-reactive sample constituents; analyze inorganics and organics simultaneously; and detect these targets in complex real world samples, without any sample preparation or cleanup steps. Earlier studies have demonstrated the ability to specifically identify cross-reactive toxins and nitroaromatics, and have identified biomolecules that can be used to identify cross-reactive divalent metal cations; the methods developed on these studies will be adapted for use on the NIEHS program. By the end of Phase II, a simple, dipstick biochip will be incubated in a few microliters of sample, and then read out automatically, in seconds, using a unique "specific transducer." Because the transducer can analyze micron-sized biomolecule pixels, the biochips will be inexpensive, and because no reagents are required and samples can be very small, Doodlebug will be very economical. PROPOSED COMMERCIAL APPLICATION: NIESH is seeking new tools for screening large populations for exposure to inorganic and organic environmental agents. However, Doodlebug will have many other applications as well, including site characterization, wastewater monitoring, food and beverage analysis, and medical diagnostics. I.e., Doodlebug can be used to help prevent human exposure by helping to clean up existing pollution, preventing future pollution, and detecting contaminants in food products; and can be used to help diagnose illness due to exposure.